Scratchers



Oct. 1 1957 HALL, 5 2,808,112

SCRATCHERS Filed March 27. 1953 IN VENTOR. desae E #414 5/:

United States Patent SCRATCHERS Jesse E. Hall, Sr., Weatherford, Tex.

Application March 27, 1953, Serial No. 345,069

5 Claims. (Cl. 166-173) This invention relates to improvements in scratchers and refers more particularly to abrading or scratching elements formed of circular bands of metal from which extend flexible wire tines or Whiskers and sometimes em ployed in the conditioning of the well bore of an oil well. The salient novelty in the present invention resides in the use of prominences or protuberances on the outer surface of the band or collar to facilitate the movement of the wires with respect to each other and with respect to the collar when the collar is reciprocated with the tubing or casing in the well.

Scratchers or abrading devices have been used principally in the conditioning of oil wells prior to cementing to scrape off the filter cake deposited thereon during the drilling operation and thereby obtain a more satisfactorybond between the cement and the earth formations. These scratchers are preferably in the form of collar supports to which are flexibly attached abrading Wires which extend nonradially from the support. The collars of the scratchers are mounted rotatively and with a limited axial movement on the casing or pipe to permit easy reversal upon reciprocation of the casing in the well.

In running the pipe into the well and during the downstroke of reciprocation, the abrading wires are inclined upwardly while on the upstroke they are inclined downwardly. In this connection it will be understood that the normal outside diameter of the scratchers is considerably more than the well bore diameter, and accordingly when introduced into the well bore the wires are confined within the narrow annular space between the casing or pipe and well bore so as to have relatively strong frictional contact with the well wall at all times during reciprocation.

A weakness in the structural design of scratchers of this type is the tendency for the abrading wires during reciprocation to foul and wrap around the adjacent wires as the scratcher is moved up and down with the casing during reciprocation. The difficulties arise either from the crossing of adjacent wires or from the wires becoming entwined or engaged with either the coil springs from which the wires extend or upon other obstructions which extend above the surface of the collar or support. To correct this difiiculty of fouling the wires and twisting them into shapes in which they do not function normally, there are located upon the support or collar, prominences or protuberances at intervals circumferentially thereof and in definite relationship with the projection point of the wires. These raised portions are so positioned with respect to the projection points of the wires that they permit a relatively unobstructed override of the wires during the reciprocation of the collar support. Descriptive of the location of the prominences it might be said that they are positioned upstream of the projection points of the wires since the wires are angularly disposed to the collar and may be said to project downstream therefrom.

An advantage therefore of the invention is to provide a scratcher comprising a collar adapted to be rotatably mounted upon a pipe or casing with abrading elements extending nonradially from its periphery and prominences or mounds arranged upon the outer surface of the collar which facilitate unobstructed passage of the wires throughout substantially a 180 are from an upright position substantially parallel with the axis of the collar to a depending position also substantially parallel with the collars axis.

Another advantage is the provision of protuberances upon the surface of the collar support located on the opposite side of the coils from the direction which the wires project and closely adjacent to the projection points to permit a relatively unobstructed override of the wires as the collar is reciprocated. v

A further advantage is to provide a plurality of coil springs interposed in the individual wires at their points of projection with prominences or protuberances formed on the collar adjacent said coil springs to prevent fouling of the wires with the other coil springs on movement of the collar during reciprocation.

Other objects and advantages of the invention will be apparent from the description which follows.

In the accompanying drawings which form a part of the instant specification and are to be read in conjunction therewith and in which like reference unmerals are used to indicate like parts in the various views:

Fig. 1 is a side elevational view of a'scratcher embodying the invention with parts shown in section;

. Fig. 2 is a view of one-half the'scratcher shown in Fig. l partly in plan and partly in section. v

Fig. 3 is a detail showing a modified form of pro tecting protuberance or prominence eliminating the flat top structure; and

Fig. 4 is a second modification of a protective prominence or protuberance which extends across the collar between two of the supporting wires.

Referring to the drawings, at 10 is showna collar sup-.

out by punching tabs or tongues 11 which serve as the gripping or anchoring members for the abrading wires. The wire abrading elements which are in the form of tines or whiskers extend from the collar in two circumferential rows; the wires in the upper row designated by the numeral 12a and the tines or whiskers in the lower row designated by the letter 12b. Interposed in the wires at the points of projection from the collar are coils 12c.- Crossover sections of the wires between the coils which in the construction shown lie within the collar are designated 12d. These crossover sections are gripped beneath the anchoring tabs or tongues 11. Holes are punched in the collar and located so the coils formed in the wires extend through the holes, as best shown in Figs. Zand 3.

Adjacent each of the coil springs and on the opposite side from which the wires project are prominences, pref erably at least as high as the height of the coils above the periphery of the collor. These prominences may be formed by pressing out the metal of the collar itself or may be applied as separate pieces of metal welded or otherwise fastened to the exterior surface of the collar. In Fig. 1 the prominences or bosses 13 are frusto-coni'cal; in shape with a flattened top 13a and are cut away at one side by the perforations in which the coil. springs; 120 are positioned thereby giving the prominences or i 3 varied from the structure-shown in Fig. l in that the flattened top :13a has i been eliminated and a dome shape adopted.

The prominences or protuberances 15 shown in Fig. 4 are-Tormed-inor appliedto the outer surface ofthe collar and extend continuously between the upper and lower rows of wires--sim1ilating=spectacles in shape. These protective 3 prominences likewise have a flattenedtop 15a to reduce 'as much as possible the diameter of the. support.

In operation a plurality of the scratchers are-mounted uponthe exterior of apipeor casing. The scratcher col lars have a-slightlygreater internal diameter than the external diameter of thepipeupon which they aremounted- Lugs or steps are-weldedto the-"pipe'above-and below the collars permitting a limited =longitudinal movement of the collars along the pipe and'free rotation of the collars' upon' the pipe. The intervals at which the scratchers-are positioned along the pipeis usually-governed by the length of strokeofreciprocation given the-pipe during the conditioning operation.

As suggested hereinbefore, as the pipeis run into the well, there is an annular space-between the pipe and well bore having a'width considerably less-than'the distance that the wires extend from-the exterior-of the collar. As a consequence, as'the casing or' pipe is run in,-the wires frictionally engage the wall of the Welland the abrading elements or tines drag or are inclined upwardly as the casing is moved downwardly into the well. When the ca'sing-or-pipe arrives at the location where-it is to be set or where the well wall is to be cleaned of mud cake, the pipe is reciprocated in the well bore for a distance upwardly and downwardly corresponding substantially to the distance betweenthe scratchers. Thus, the well wall is'abra'ded by the scratcher wires throughout the zone to be conditioned. During the downstroke'the stops above the collars of the scratchers contact the top rim ot 'the collar untilthe direction "of the pipe is reversed. Upon reversal of the direction of't-he'pipe or as-the upstroke commences, the lugs below the collar contact the lower rim of the collars and the-wires or abrading-elernents pivot at their ends'in the well wall causing the collars to pass through the wires-while they. are being held closely against the periphery of the collars.

Due to the fact that the wires extend nonradially from the collar, all in the same direction, and are closely wrapped about the-periphery of the collar on account of their confinement within the narrow annular space between the'pipe and well bore, it is inevitable that the wires will "foul or become entwined with each otheror with the coil springs from which the wires extend unless some provision is made for them to override freely. This is accomplished by strategically locating the protuberances or promi-nences upon the outer-surface of the collar at locations which permit a relatively unobstructed override of the wires and the coils from which the-wires extend. Upon each reciprocation of the pipe and reversal of the scratcher wires, this difficulty arises, since with each stroke of the casing,the collar reverses its travel andmust pass through the wires in a reverse direction. Thisnecessitates a structure that will permit the wires to freely override the adjacent wires and coils when the scratchers are moved in either direction during reciprocation. Entanglement of the wires with each other or with the coils not only destroys their usefulness and function but exposes them-'to'the abrasive action of the well'bore causing failure and almost immediate destruction of wires as operative elements of the scratcher.

Thus it will be seen that there has been provided a scratcherconstruction having protective mounds 1 or --protuberances upon the periphery of the collar support which will permit a relatively unobstructed passage of the collar through the wires during reciprocation of the scratchers with a minimum of fouling or entanglement of the wires, either upon themselves or upon the coil springs from which they extend.

It will be understood that certain features and subcombinations are of-.utility-and, maybe employed without reference to other'features and subcombinations. This is contemplated .by land. isiwithin .therscope: ofitheclaims.

It is further obvious that various changes may be made in details within the scope of'the claims without departing from the spirit of the invention. Therefore it is to be understood that the invention is not limited to the specific details shown and described.

Having thus described my.invention, I claim:

1. In a well bore cleaning scratcher, a circular collar dimpled interiorly to form integral raisedbosses on its exterior surface, said bosses 'being .at circumferentially spaced intervals .aroundthe collar, saidcollar having .an apertureibeside eachboss, all of said apertures'being.circumferentially olfset'in the same direction from therespective bosses, and a plurality of coil mounted .abrading wires, eachhaving its coil located in: one of said apertures with the wire projecting away,from the. adjacent" boss to apoint beyond but spaced outwardly'from the next-boss, whereby all of said wires have a si'dewise inclination in the same direction-relative to said collar. 2. A scratcher as in claim 1 .wherein .each aperture intersects the associatedboss whereby part of the aper ture extends through'the boss and-the balance extends through. a portion of the collar adjacent to the boss.

3. In a well bore cleaning scratcher, a circular collar.

containing a series of apertures, said apertures being at circumferentially spaced-intervals around the collar, a plurality of abrading wires'each extending through one of said apertures. and having a portion secured to the interior of the collar adjacentto such aperture, each wire being coiled at the point where it passes through the associated aperture to form a spring, said .collar having beside .each aperture an integral boss raised onits .exterior surface, all of said bosses'being circumferentially offset in the same direction from their respective apertures, the height of each boss being at leastequal to'the distancethat the coil in the adjacent aperture projects .out ofthe aperture,

thereby to form a shield on one side of such coil, andeach wire extending exteriorly of the collar 'away from its shieldingbossto a point beyond but spaced outwardly from the next.boss,;whereby. all of said wires have a sidewise inclination in .the same direction relative :to-"said collar.

4. A scratcher as in claim3 wherein each boss is frustoconical in shape.

5. A scratcher as in claim 3 wherein eachboss isgenerally crescent-shaped and has the, coil of the associated wire located in the concave side of the crescent.

References Cited -in the file of this-patent UNITED STATESPATENTS 2,506,405 Wright -May.2,=1=950 2,674,317 Kipper Apr. 6, .1954

FOREIGN PATENTS 667,707 Great Britain Mar. .5, .1952 

